In the field of firefighting, spanner wrenches are used to tighten and loosen firefighting apparatus couplings. Couplings vary in size and design depending on their function and/or manufacturer. For example, a typical firefighting job might require a fireman to work with couplings ranging from 11/4 inches in diameter to 31/2 inches in diameter. At the same time, coupling designs encountered during the job may vary to include a pin-type as shown in the cross-section of FIG. 1(a), a lug-type shown in the cross-section of FIG. 1(b), a squared lug-type shown in the cross-section of FIG. 1(c), and/or a recessed hole-type shown in the cross-section of FIG. 1(d). Naturally, it is desirable that a fireman only carry a single spanner wrench that works with all of the above designs and sizes.
Accordingly, prior art spanner wrench tools for firefighting are designed with either a fixed jaw or a movable jaw pivotable about a single hinge point to accommodate the largest coupling diameter that will be encountered. In either case, however, the effectiveness of these wrenches diminishes as the size of the coupling decreases. Furthermore, use of these wrenches can damage the smaller couplings over a period of time For a better understanding of this problem, reference is made to FIG. 2 where a prior art spanner wrench 10 is shown from a side view and positioned on a smaller (e.g. 11/4 inch diameter) lug-type coupling 20.
As is readily apparent, a jaw 12 includes a square tooth 14 for catching on a lug 22 of coupling 20. As a user applies a force in the direction of arrow A on a handle 16, a turning force results in the direction of arrow B. Simultaneously, a compressive force indicated by arrow C is exerted on coupling 20 and is a force proportional to that applied by arrow A. The line of force, created by the force at arrow C and indicated by dashed line 30, falls after the center 24 of coupling 20. This results in compression of coupling 20 which causes tooth 14 to slip from lug 22. Furthermore, since many couplings are made from brass or aluminum alloys, the lugs wear down over time under this type of compressive force thereby increasing the chance that the spanner wrench will slip from the lug.
Thus, the need exists for a spanner wrench that is effective with a wide variety of coupling sizes and designs, and more specifically for a spanner wrench that is especially effective in the hurried environment of fire or rescue emergencies. Therefore, an object of the present invention is to provide a spanner wrench for firefighters that may be adjusted to function with a range of coupling sizes and designs without damaging the couplings over time. In addition, it is desirable that a spanner wrench be useful to a firefighter for other operations that typically require crescent wrenches, a hammer, screwdrivers, etc. Accordingly, another object of the present invention is to provide a spanner wrench for firefighters that also incorporates a plurality of other tools commonly used by firefighters thereby resulting in a spanner wrench and combination tool for firefighters.